Again, after 3 hours measure a pH of 4.51.
The starter became more alive with larger
bubbles and its surface bulging. Due to the
increase in volume and a possible larger
rise made the 1 qt (1 l) container inadequate
and everything was moved to a larger bowl.
There, 180 water and 180 g flour was added.

continuing to grow 540 g ripe leaven sponge

starting to bulge

pH of 4.60

more bulging

bigger bubbles

Since I am attempting to follow the SF recipe which calls for a higher temperature for
growing the sponge, the bowl is put in a
warmer spot which is around 80 F (26 C).
Three hours into fermenting this stage, the
pH is 4.60, the starter is bulging more,
and big bubbles show.